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Citation

International Council for the Exploration of the Sea (2010). Report of the Working Group on Marine Mammal Ecology (WGMME). Report by International Council for the Exploration of the Sea (ICES). pp 212.

Abstract:

The Working Group on Marine Mammal Ecology (WGMME) met at the University of the Azores in Horta, The Azores from 12 April to 15 April 2010. Sinéad Murphy chaired the meeting of 25 participants, representing twelve countries.

Seven different ToRs were assessed, covering a wide range of issues, including reviewing the effects of wind farm construction and operation on marine mammals and assessing the current contaminant loads in marine mammals within the ICES Area. Other topics included reviewing population abundance, structure and status of marine mammals off the Azores, further development of a framework for surveillance and monitoring of marine mammals, evaluating the scope for a European marine mammal tissue bank, assessing the current status of the Saimaa ringed seal popula‐tion, grey seal prey consumption in UK waters, and further development of the ICES seal database. The European Commission also requested an assessment of the population status of cetaceans concerned by EC Regulation 812/2004.

The WG outlined and reviewed the potential negative impacts of wind farms (construction and operation) on marine mammals and provided advice on research needs, monitoring and mitigation schemes. The WG made a number of recommendations with regard to wind farm developments, including the establishment of means for efficient dissemination of results of common interest and means of making available previous EIA reports and previously collected baseline data for subsequent studies and assessments. The WG also recommended that multinational studies should be undertaken, and management decisions regarding offshore wind farms should be based on appropriate populations and/or management units for the relevant marine mammal species, irrespective of national borders. Further, development of methods to assess the cumulative effects on marine mammals of the underwater noise level caused by the simultaneous wind farm construction and operation at nearby sites. Other recommendations relate to improving our understanding of the characterization sources of underwater noise associated with the construction and operation of offshore wind farms, establishing common accepted tolerance limits for acute noise exposure in marine mammals and the development of common guidelines for mitigation in relation to pile driving.

An overview on current contaminant loads in marine mammals inhabiting the ICES Area is presented within this report, and highlights (regions and) marine mammal populations at highest risk from environmental exposure. Further, the cause–effect relationships between contaminants and health status, and the population‐level effects of environmental impacts were also assessed. Despite being banned for two to three decades, polychlorinated biphenyls (PCBs) still occur at concentrations that exceed proposed thresholds for mammalian toxicity in some marine mammal top predator species, including bottlenose dolphins, killer whales and polar bears. Compared with many other legacy pollutants, PCBs are declining only very slowly in many geographic regions (e.g. harbour porpoises in UK waters). Given the high levels of PCBs in marine mammals (compared with proposed toxicity thresholds), the resistance of PCBs to environmental degradation and their relative toxicity, PCBs undoubtedly continue to pose the greatest toxicological threat to some marine mammal species within the ICES Area. The WG recommended that research is needed to assess trends in contaminant exposure (PCBs and newer contaminants) and to conduct risk assessments for health and reproductive effects from contaminant exposure in species of highest risk (e.g. killer whales, St Lawrence belugas, polar bears, bottlenose dolphins, and Baltic marine mammals).